The Rheo Knee from MIT adjusts and learns on the go

Hugh Herr, a researcher at MIT, has developed a computer controlled artificial knee that learns your walking style over time and can adapt to short term terrain changes. It's called the "Rheo Knee," and the
prosthetic works to provide resistance and walking control by stiffening and relaxing a magnetic fluid in the joint. Herr, an amputee himself, says the technology allows rapid changes between a freely swinging and locked up leg, much like a car break, and allows for nearly any activity, minus swimming. He also calls the substance magnetorheological fluid, but we're pretty sure he's just making that part up to throw us. Nice try Hugh.